Ring cooling fan

ABSTRACT

A ring cooling fan includes a fan hub including a top surface and a bottom surface disposed apart from the top surface along an axis of rotation of the ring cooling fan for connection with a drive shaft or a clutch body. A first fan blade including a first distal end and a first proximal end opposite the first distal end is connected with the fan hub. A second fan blade including a second distal end and a second proximal end opposite the second distal end is connected with the fan hub. A fan ring without an external stiffening portion is connected with the first distal end of the first fan blade and the second distal end of the second fan blade.

FIELD OF THE INVENTION

[0001] The present invention relates to a cooling fan, and, more specifically, to an improved ring cooling fan.

BACKGROUND OF THE INVENTION

[0002] In an internal combustion engine (e.g., a diesel or a gasoline engine), a known or conventional ring cooling fan regulates a temperature of an engine coolant that cools the engine by drawing and/or pushing air through a heat conducting radiator. It is known to use an outer ring to connect a multiplicity of fan blades to one another. FIG. 5 shows an example of the conventional ring cooling fan 100 including multiple fan blades 110 and an outer ring 120.

[0003] As shown in FIG. 5, the outer ring 120 includes a first portion 121 and a second portion 123 connected with the first portion 121, such that the outer ring 120 has an about L-shaped cross-section. The first portion 121 is in the form of a connecting portion that connects a distal end of each of the fan blades 110. The second portion 123 is in the form of an external stiffening portion that stiffens the outer ring 120. It is known to form the conventional ring cooling fan 100 by injecting molten plastic into a mold in an injection molding process. By the use of the external stiffening portion, warpage of the conventional ring cooling fan 100 after removal from the mold and during subsequent cooling is decreased.

[0004] Further, the first portion 121 extends an entire length of a corresponding length of each of the fan blades 110 along an axis of rotation of the conventional ring cooling fan 100, such that the fan blades 110 are completely disposed within a cylinder having a height equal to the length of the first portion 121 along the axis. By the use of such a connecting portion, noise generated by the operation of the conventional ring cooling fan 100 can be decreased.

[0005] However, the conventional ring cooling fan 100 suffers from a number of disadvantages associated with the above-discussed structure of the outer ring 120. Molding of the first portion 121 and of the second portion 123 requires a large amount of plastic material. The use of the large amount of plastic increases costs related to the conventional ring cooling fan 100. Also, there is increased stress between the fan blades 110 and the outer ring 120 at and/or near the areas and/or volumes of connection therebetween. Finally, having the first portion 121 extend the entire length of the corresponding length of the fan blades 110 impedes air flow through the conventional ring cooling fan 100.

[0006] Thus, an improved ring cooling fan is desired that avoids the above-discussed disadvantages. For example, it is desirable to obtain a ring cooling fan that provides decreased stresses between fan blades and a fan ring. It is also desirable to obtain a ring cooling fan that provides improved air flow. It is further desirable to obtain a ring cooling fan that provides decreased noise during operation.

SUMMARY OF THE INVENTION

[0007] The present invention provides a ring cooling fan including a fan hub having a top surface and a bottom surface disposed apart from the top surface along an axis of rotation of the ring cooling fan for connection with a drive shaft or a clutch body. A first fan blade including a first distal end and a first proximal end opposite the first distal end is connected with the fan hub. A second fan blade including a second distal end and a second proximal end opposite the second distal end is also connected with the fan hub. A fan ring without an external stiffening portion is connected with the first distal end of the first fan blade and the second distal end of the second fan blade.

[0008] The present invention further provides a ring cooling fan including a fan hub having a top surface and a bottom surface disposed apart from the top surface along an axis of rotation of the ring cooling fan for connection with a drive shaft or a clutch body. A first fan blade including a first distal end and a first proximal end opposite the first distal end is connected with the fan hub. A second fan blade including a second distal end and a second proximal end opposite the second distal end is connected with the fan hub. A fan ring that does not include an about L-shaped cross-section is connected with the first distal end and the second distal end.

[0009] The present invention further provides a ring cooling fan including a fan hub having a top surface and a bottom surface disposed apart from the top surface along an axis of rotation of the ring cooling fan for connection with a drive shaft or a clutch body. A first fan blade including a first distal end and a first proximal end opposite the first distal end is connected with the fan hub. A second fan blade including a second distal end and a second proximal end opposite the second distal end is also connected with the fan hub. A fan ring is connected with the first distal end and the second distal end. A first winglet is connected between the first fan blade and a first portion of the fan ring. The fan ring can include an about L-shaped cross-section having an external stiffening portion. However, preferably the fan ring does not include such a stiffening portion.

[0010] The present invention further provides a process of producing a ring cooling fan including a fan hub, a first fan blade including a first distal end and a first proximal end opposite the first distal end and connected with the fan hub, a second fan blade including a second distal end and a second proximal end opposite the second distal end and connected with the fan hub, and a fan ring connected with the first distal end of the first fan blade and the second distal end of the second fan blade. The process includes disposing the fan hub in a mold, molding the fan ring without an external stiffening portion to the first distal end of the first fan blade and to the second distal end of the second fan blade, and removing the ring cooling fan from the mold.

[0011] The present invention further provides a process of producing a ring cooling fan including a fan hub, a first fan blade including a first distal end and a first proximal end opposite the first distal end and connected with the fan hub, a second fan blade including a second distal end and a second proximal end opposite the second distal end and connected with the fan hub, a fan ring connected with the first distal end of the first fan blade and the second distal end of the second fan blade, and a winglet. The process includes disposing the fan hub in a mold, molding the fan ring without an external stiffening portion to the first distal end of the first fan blade and to the second distal end of the second fan blade, and removing the ring cooling fan from the mold.

[0012] The present invention further provides a process of producing a ring cooling fan including a fan hub, a first fan blade including a first distal end and a first proximal end opposite the first distal end and connected with the fan hub, a second fan blade including a second distal end and a second proximal end opposite the second distal end and connected with the fan hub, a fan ring connected with the first distal end of the first fan blade and the second distal end of the second fan blade, and a winglet. The process includes disposing the fan hub in a mold, molding the fan ring to the first distal end of the first fan blade and to the second distal end of the second fan blade, and removing the ring cooling fan from the mold.

[0013] The present invention further provides a process of installing one or more winglets on a separately produced ring cooling fan. The process includes installing one or more of the winglets on a separately produced ring cooling fan by any suitable manner of attachment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

[0015]FIG. 1 shows a bottom isometric view of the ring cooling fan of the present invention.

[0016]FIG. 2 shows a top view of the ring cooling fan of FIG. 1.

[0017]FIG. 3 shows side view of the ring cooling fan of FIG. 1.

[0018]FIGS. 4a and 4 b show top and bottom views, respectively, of the ring cooling fan of FIG. 1 including winglets.

[0019]FIG. 5 shows a cross-sectional view of a conventional ring cooling fan.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Examples of preferred embodiments of the present invention will now be described with reference to the drawings, wherein like reference numbers throughout the several views identify like elements. FIGS. 1-4 show an example of a ring cooling fan according to the present invention.

[0021] As exemplified in the drawings, the preferred ring cooling fan 10 includes a fan hub 20, a plurality (i.e., at least two (2), preferably six (6) or more, and more preferably ten (10) or more) of fan blades 30, a fan ring 40, and optionally a plurality of stiffening ribs 50 (each discussed below).

[0022] In a broad embodiment, the fan hub 20 couples the fan blades 30 with a drive shaft (not shown) or a clutch body (not shown). By this arrangement, a rotation of the drive shaft or clutch body about an axis of rotation results in a corresponding revolution of the fan blades 30/ring cooling fan 10. It is to be understood that although the fan hub 20 and its associated structure shown in the drawing figures exemplify preferred embodiments, the fan hub 20 can include any structure so long as the fan hub 20 couples with the fan blades 30 for rotation about the axis.

[0023] As exemplified in the drawings, the fan hub 20 includes a top surface 21 and a bottom surface 23 that is offset from the top surface 21 along the axis of rotation of the fan hub 20/the ring cooling fan 10 for connection with the drive shaft or the clutch body. Each of the top and bottom surfaces 21, 23, has a generally circular cross section, and includes portions that are disposed on successive parallel planes (i.e., neither of the top and bottom surfaces 21, 23, are required to lie entirely on a single plane). By this arrangement, in a preferred embodiment, the fan hub 20 is generally cup-shaped.

[0024] As exemplified in the figures, a plurality of about-circular holes 25 is used to connect the fan hub 20 with the drive shaft or the clutch body. The plurality of about-circular holes 25 is preferably about equally spaced on the fan hub 20. In a preferred embodiment, the plurality of about-circular holes 25 includes four (4) holes that are disposed about 90 degrees apart. However, it is to be understood that the plurality of about-circular holes 25 can include any number of holes, each being of any size or shape, and can be disposed at a variety of positions on or along the fan hub 20. It is to be further understood that satisfactory attachment of the fan hub 20 with the drive shaft or the clutch body can be achieved in the absence of the plurality of about-circular holes 25.

[0025] Optionally, the fan hub 20 can include a plurality of radial slots 27. The radial slots 27 permit dissipation of heat from the clutch body. The plurality of radial slots 27 is about equally spaced on the fan hub 20. In a preferred embodiment, the plurality of radial slots 27 includes four (4) slots that are disposed about 90 degrees apart. However, it is to be understood that the plurality of radial slots 27 can include any number of holes or slots, each being of any size or shape, and can be disposed at a variety of positions on or along the fan hub 20.

[0026] Optionally, the fan hub 20 can include one or more interface holes (not shown) disposed on an outer diameter thereof. The interface holes can be used for flow through of liquid plastic during an injection molding process of the ring cooling fan 10. By this arrangement, the fan blades 30 can be secured to the fan hub 20. In a preferred embodiment, the fan hub 20 includes thirty six (36) such interface holes, each having a diameter of between 11 and 12 mm. However, it is to be understood that any number of interface holes can be used, each being of any size or shape, disposed at a variety of positions on or along the diameter of the fan hub 20. It is to be further understood that satisfactory attachment of the fan blades 30 with the fan hub 20 can be achieved in the absence of the interface holes on the fan hub 20.

[0027] The fan hub 20 can be of a variety of materials, including plastics and metals. In a preferred embodiment, the fan hub 20 is a metal capable of being disposed in a mold, such that at least a portion of the ring cooling fan 10 can be molded directly thereon. Specifically, the material can be steel, such as 050 YHK hot roll steel, aluminum, or glass filled nylon. However, it is to be understood that the fan hub 20 can be of any material able to substantially permit operation under the desired operating conditions of the ring cooling fan 10.

[0028] In a broad embodiment, the plurality (i.e., at least two) of the fan blades 30 is connected with the fan hub 20, such that the fan blades 30 effectively cool the engine. As exemplified in the drawings, in a preferred embodiment, the plurality of fan blades 30 includes six (6) or more fan blades 30, and, more preferably includes ten (10) or more fan blades 30. It is to be understood that although the fan blades 30 and their associated structure shown in the drawing figures exemplify preferred embodiments, the fan blades 30 can include any structure so long as the fan blades 30 effectively cool the engine.

[0029] As exemplified in the drawings, each of the fan blades 30 includes a proximal end 31 that is connected with the hub 20 and a distal end 33 that is disposed apart from the proximal end 31 and connected with the fan ring 40. Contours and/or pitches of each of a top blade surface 35 and the bottom blade surface 37 are selected based on the desired operating conditions and/or cooling requirements of the ring cooling fan 10. As exemplified in the figures, at least two, and preferably, all of the distal ends 33 of the fan blades 30 are connected to each other via the fan ring 40 (discussed below). Each of the fan blades 30 includes a leading edge 38 adjacent to the top surface 21 of the fan hub 20, and a trailing edge 39 that is opposite the leading edge 38 and adjacent to the bottom surface 23 of the fan hub 20.

[0030] In a broad embodiment, the fan ring 40 does not include an external stiffening portion or portions (e.g., does not include an about L-shaped cross-section having a stiffening flange) and is connected with at least two of the fan blades 30. By this arrangement, stress between the fan blades 30 and the fan ring 40 at and/or near an area and/or volume of attachment therebetween can be decreased. Further, the amount of material required to mold the ring cooling fan 10 can be decreased, thereby decreasing the cost of material. Although the drawings show preferred embodiments of the fan ring 40, it is to be understood that the fan ring 40 can be of any cross-sectional shape, and can connect any of a plurality of the fan blades 30 at any location along the length of the fan blades 30, so long as the fan ring 40 does not include an external stiffening portion or portions.

[0031] As exemplified in the drawings, a preferred embodiment of the fan ring 40 has an about rectangular cross-section, and more preferably, has an about rectangular cross-section that is an about trapezoidal cross-section including one or more draft surfaces to facilitate removal of the ring cooling fan 10 from a mold during the injection molding process.

[0032] The fan ring 40 includes a top edge 41 and a bottom edge 43 opposite the top edge 41. In a preferred embodiment, as exemplified in the drawings, the fan ring 40 has a length between the top and bottom edges 41, 43, that is less than a corresponding length of one or more of the fan blades 30 along the axis of rotation of the ring cooling fan 10. The top edge 41 of the fan ring 40 is disposed at an elevation about the same as that of the leading edge 38 of one or more of the fan blades 30, such that the bottom edge 43 of the fan ring 40 is disposed at an elevation between (i) the leading edge 38 of one or more of the fan blades 30 and (ii) the trailing edge 39 of one or more of the fan blades 30. By this arrangement, an optimum position of the fan blades 30 within the fan ring 40 can be achieved, such that air flow through the ring cooling fan 10 is maximized and/or is not impeded unnecessarily by the fan ring 40.

[0033] However, it is to be understood that the top and bottom edges 41, 43, of the fan ring 40 can be disposed at any elevations relative to the leading and trailing edges 38, 39, of any of the fan blades 30, and that the length of the fan ring 40 between the top and bottom edges 41, 43, can be greater than, less than, or equal to the corresponding length of one or more of the fan blades 30 along the axis of rotation of the ring cooling fan 10. For example, the fan ring 40 can have a length that is about equal to a corresponding length of the fan blades 30 along the axis of rotation of the ring cooling fan 10. Further, the top edge 41 of the fan ring 40 can be disposed at an elevation that is different than that of the leading edge 38 of one or more of the fan blades 30, and the bottom edge 43 of the fan ring 40 can be disposed at an elevation different than that of the trailing edge 39 of one or more of the fan blades 30. As another example, the top edge 41 of the fan ring 40 can be disposed at an elevation about the same as that of the leading edge 38 of one or more of the fan blades 30, and the bottom edge 41 of the fan ring 40 can be disposed at an elevation about the same as that of the trailing edge 39 of one or more of the fan blades 30.

[0034] The ring cooling fan 10 can include one or more of the winglets 60 to attach a portion of the one or more of the fan blades 30 to one or more portions of the fan ring 40. Preferably, the ring cooling fan 10 includes a plurality of winglets 60, and more preferably, includes the same number of winglets 60 as the number of the fan blades 30 included in the ring cooling fan 10. As exemplified in the drawings, in a preferred embodiment, the winglet 60 is connected between a length of the fan blade 30 and the fan ring 40. Preferably, the winglet 60 is connected between the trailing edge 39 of the fan blade 30 and a portion of the fan ring 40, and more preferably is connected between an edge of the distal end 33 of the fan blade 30 and a portion of the bottom edge 43 of the fan ring 40. By this arrangement, stress at and/or near the area and/or volume of connection between the fan blades 30 and the fan ring 40 can be distributed over a larger area and/or volume, thereby decreasing stress concentration at the area and/or volume or connection. Further, it is believed that the use of the winglets 60 can increase air flow through the ring cooling fan 10, and/or can decrease operating noise resulting from the use of fan ring 40 where the top and bottom edges 41, 43, of the fan ring 40 are not disposed at an elevation which is about the same as that of the leading and trailing edges 38, 39, respectively, of one or more of the fan blades 30.

[0035] In a preferred embodiment, as exemplified in the drawings, the winglets 60 are about triangular in shape. The winglets 60 can be molded in an injection molding operation with other components of the ring cooling fan 10 (e.g., the fan blades 30, the fan ring 40, etc.). Alternatively, the winglets 60 can be produced as components that are separate from one or more of the other components of the ring cooling fan 10 and attached to the ring cooling fan 10 after the molding process. Thus, it is to be further understood that the winglets 60 can be connected with the ring cooling fan 10 by any method of attachment.

[0036] Although the drawings show preferred embodiments of the winglets 60 in a ring cooling fan 10 having a fan ring 40 without an external stiffening portion, it is to be understood that the winglets 60 can be used in any ring cooling fan assembly, including known and/or conventional structures, to provide the above-discussed advantages. For example, the winglets 60 can be used in a known ring cooling fan that includes a fan ring with an about L-shaped cross-section and/or having an external stiffening portion.

[0037] In a broad embodiment, the stiffening ribs 50 are optionally disposed on one or more of the top and bottom surfaces 35, 37, of one or more of the fan blades 30, to decrease warpage and/or catastrophic failure or “bursting” during operation at increased revolution rate of the fan blades 30. As exemplified in the drawings, in a preferred embodiment, the stiffening ribs 50 are used on both top and bottom surfaces 35, 37, of the ring cooling fan 10. However, it is to be understood that the stiffening ribs 50 can be used on either, both, or neither of the sides of the fan blades 30. Further, the heights, number, size, shape, spacing, orientation, and material of the stiffening ribs 50 can be selected such that the desired characteristics of the ring cooling fan 10 are achieved. The open- and closed-box structures of the stiffening ribs 50 are discussed in copending application Ser. No. 10/196,268, filed Jul. 17, 2002, the disclosure of which is incorporated by reference herein in its entirety.

[0038] As discussed above, the ring cooling fan 10 is preferably manufactured by an injection molding process. The process can include disposing the fan hub in a mold, molding the fan ring without an external stiffening portion to the first and distal end of the first fan blade and to the second distal end of the second fan blade, and removing the ring cooling fan from the mold. The ring cooling fan can optionally include one or more winglets molded or produced thereon. Alternatively, the process can include installing one or more of the winglets on the ring cooling fan after it is separately molded or produced.

[0039] In another embodiment, one or more of the winglets can be installed on a ring cooling fan including a fan ring that has an L-shaped cross-section. This process includes disposing the fan hub in a mold, molding the fan ring to the first distal end of the first fan blade and to the second distal end of the second fan blade, and removing the ring cooling fan from the mold. The ring cooling fan can include one or more winglets molded or produced thereon. Alternately, the process can include installing one or more of the winglets on the ring cooling fan after it is separately molded or produced.

[0040] Numerous additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein. 

What we claim is:
 1. A ring cooling fan, comprising: a fan hub comprising a top surface and a bottom surface disposed apart from the top surface along an axis of rotation of the ring cooling fan; a first fan blade comprising a first distal end and a first proximal end opposite the first distal end and connected with the fan hub; a second fan blade comprising a second distal end and a second proximal end opposite the second distal end and connected with the fan hub; and a fan ring connected with the first distal end of the first fan blade and the second distal end of the second fan blade, wherein the fan ring does not have an external stiffening portion.
 2. The ring cooling fan according to claim 1, wherein the fan ring has a length that is about equal to a corresponding length of the first and second fan blades along the axis of rotation.
 3. The ring cooling fan according to claim 2, wherein the first fan blade comprises a first leading edge and a first trailing edge opposite the first leading edge and adjacent to the bottom surface of the fan hub, the second fan blade comprises a second leading edge and a second trailing edge opposite the second leading edge and adjacent to the bottom surface of the fan hub, the fan ring comprises a top edge and a bottom edge opposite the top edge and adjacent the bottom surface of the fan hub, and the top edge is disposed at an elevation different than that of the first and second leading edges and the bottom edge is disposed at an elevation different than that of the first and second trailing edges.
 4. The ring cooling fan according to claim 2, wherein the first fan blade comprises a first leading edge and a first trailing edge opposite the first leading edge and adjacent to the bottom surface of the fan hub, the second fan blade comprises a second leading edge and a second trailing edge opposite the second leading edge and adjacent to the bottom surface of the fan hub, the fan ring comprises a top edge and a bottom edge opposite the top edge and adjacent the bottom surface of the fan hub, and the top edge is disposed at an elevation about the same as that of the first and second leading edges and the bottom edge is disposed at an elevation about the same as that of the first and second trailing edges.
 5. The ring cooling fan according to claim 1, wherein the fan ring has a length that is less than a corresponding length of the first and second fan blades along the axis of rotation.
 6. The ring cooling fan according to claim 5, wherein the first fan blade comprises a first leading edge and a first trailing edge opposite the first leading edge and adjacent to the bottom surface of the fan hub, the second fan blade comprises a second leading edge and a second trailing edge opposite the second leading edge and adjacent to the bottom surface of the fan hub, the fan ring comprises a top edge and a bottom edge opposite the top edge and adjacent the bottom surface of the fan hub, and the top edge is disposed at an elevation about the same as that of the first and second leading edges such that the bottom edge is disposed at an elevation between (i) the first and second leading edges and (ii) the first and second trailing edges.
 7. The ring cooling fan according to claim 1, wherein the fan ring has a length that is greater than a corresponding length of the first and second fan blades along the axis of rotation.
 8. The ring cooling fan according to claim 1, wherein the fan ring has an about rectangular cross-section.
 9. The ring cooling fan according to claim 8, wherein the fan ring has an about trapezoidal cross-section.
 10. The ring cooling fan according to claim 1, further comprising: a winglet connected between one of the fan blades and the fan ring.
 11. The ring cooling fan according to claim 2, further comprising: a winglet connected between one of the fan blades and the fan ring.
 12. The ring cooling fan according to claim 3, further comprising: a winglet connected between one of the fan blades and the fan ring.
 13. The ring cooling fan according to claim 4, further comprising: a winglet connected between one of the fan blades and the fan ring.
 14. The ring cooling fan according to claim 5, further comprising: a winglet connected between one of the fan blades and the fan ring.
 15. The ring cooling fan according to claim 6, further comprising: a winglet connected between one of the fan blades and the fan ring.
 16. The ring cooling fan according to claim 10, wherein the first fan blade comprises a first leading edge and a first trailing edge opposite the first leading edge and adjacent to the bottom surface of the fan hub, the second fan blade comprises a second leading edge and a second trailing edge opposite the second leading edge and adjacent to the bottom surface of the fan hub, the fan ring comprises a top edge and a bottom edge opposite the top edge and adjacent the bottom surface of the fan hub, and the winglet is connected between the first trailing edge and a first portion of the bottom edge of the fan ring.
 17. The ring cooling fan according to claim 10, wherein the number of winglets is equal to the number of fan blades.
 18. The ring cooling fan according to claim 10, wherein the fan ring, the fan blades, and the winglet are molded in an injection molding operation.
 19. A ring cooling fan, comprising: a fan hub comprising a top surface and a bottom surface disposed apart from the top surface along an axis of rotation of the ring cooling fan; a first fan blade comprising a first distal end and a first proximal end opposite the first distal end and connected with the fan hub; a second fan blade comprising a second distal end and a second proximal end opposite the second distal end and connected with the fan hub; and a fan ring connected with the first distal end and the second distal end, wherein the fan ring does not have an about L-shaped cross section.
 20. A ring cooling fan, comprising: a fan hub comprising a top surface and a bottom surface disposed apart from the top surface along an axis of rotation of the ring cooling fan; a first fan blade comprising a first distal end and a first proximal end opposite the first distal end and connected with the fan hub; a second fan blade comprising a second distal end and a second proximal end opposite the second distal end and connected with the fan hub; a fan ring connected with the first distal end and the second distal end; and a winglet connected between the first fan blade and a first portion of the fan ring.
 21. The fan ring according to claim 20, wherein the fan ring comprises an about L-shaped cross-section.
 22. The fan ring according to claim 20, wherein the number of winglets is equal to the number of fan blades. 